package com.example.test_1_21.mqserver.datacenter;

import com.example.test_1_21.common.MQException;
import com.example.test_1_21.mqserver.core.Binding;
import com.example.test_1_21.mqserver.core.Exchange;
import com.example.test_1_21.mqserver.core.MSGQueue;
import com.example.test_1_21.mqserver.core.Message;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;

//统一管理内存中所有的数据
//该类后续提供的方法，可能会在多线程环境下使用，因此要注意线程安全
public class MemoryDataCenter {
    //key是exchangeName，value是Exchange对象
    private ConcurrentHashMap<String, Exchange> exchangeMap=new ConcurrentHashMap<>();
    //key是queueName，value是MSGQueue对象
    private ConcurrentHashMap<String, MSGQueue> queueMap=new ConcurrentHashMap<>();
    //第一个key是exchangeName，第二个key是queueName
    private ConcurrentHashMap<String,ConcurrentHashMap<String, Binding>> bindingsMap=new ConcurrentHashMap<>();
    //key是messageId，value是Message对象
    private ConcurrentHashMap<String, Message> messageMap=new ConcurrentHashMap<>();
    //key是queueName，value是一个Message的链表
    private ConcurrentHashMap<String, LinkedList<Message>> queueMessageMap=new ConcurrentHashMap<>();
    //第一个key是queueName，第二个key是MessageId
    private ConcurrentHashMap<String,ConcurrentHashMap<String,Message>> queueMessageWaitAckMap=new ConcurrentHashMap<>();

    public void insertExchange(Exchange exchange) {
        exchangeMap.put(exchange.getName(), exchange);
        System.out.println("[MemoryDataCenter] 新交换机添加成功！exchangeName=" + exchange.getName());
    }

    public Exchange getExchange(String exchangeName){
        return exchangeMap.get(exchangeName);
    }

    public void deleteExchange(String exchangeName){
        exchangeMap.remove(exchangeName);
        System.out.println("[MemoryDataCenter] 交换机被移除！exchangeName="+exchangeName);
    }

    public void insertQueue(MSGQueue queue){
        queueMap.put(queue.getName(),queue);
        System.out.println("[MemoryDataCenter] 新队列添加成功！queueName=" + queue.getName());
    }

    public MSGQueue getQueue(String queueName){
        return queueMap.get(queueName);
    }

    public void deleteQueue(String queueName){
        queueMap.remove(queueName);
        System.out.println("[MemoryDataCenter] 队列被移除！queueName=" + queueName);
    }

    public void insertBinding(Binding binding) throws MQException {
//        //先使用exchangeName查询对应的哈希表是否存在，不存在就创建
//        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.get(binding.getExchangeName());
//        if(bindingMap==null){
//            bindingMap=new ConcurrentHashMap<>();
//            bindingsMap.put(binding.getExchangeName(),bindingMap);
//        }
        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.computeIfAbsent(binding.getExchangeName(),k->new ConcurrentHashMap<>());
        synchronized (bindingMap){
            //再根据queueName查一下。如果已经存在，就抛出异常，不能存在才能插入
            if(bindingMap.get(binding.getQueueName())!=null){
                throw new MQException("[MemoryDataCenter] 绑定已存在！exchangeName="+binding.getExchangeName()+",queueName="+binding.getQueueName());
            }
            bindingMap.put(binding.getQueueName(),binding);
        }
        System.out.println("[MemoryDataCenter] 新绑定添加成功！exchangeName=" + binding.getExchangeName()+",queueName=" + binding.getQueueName());
    }

    //获取绑定：1、根据exchangeName和queueName确定唯一一个Binding；2、根据exchangeName获取到所有的Binding
    public Binding getBinding(String exchangeName,String queueName){
        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.get(exchangeName);
        if(bindingMap==null){
            return null;
        }
        return bindingMap.get(queueName);
    }

    public ConcurrentHashMap<String,Binding> getBindings(String exchangeName){
        return bindingsMap.get(exchangeName);
    }

    public void deleteBinding(Binding binding) throws MQException {
        ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.get(binding.getExchangeName());
        if(bindingMap==null){
            //该交换机没有绑定任何队列，报错
            throw new MQException("[MemoryDataCenter] 绑定不存在！exchangeName="+binding.getExchangeName()+"，queueName="+binding.getQueueName());
        }
        bindingMap.remove(binding.getQueueName());
        System.out.println("[MemoryDataCenter] 绑定删除成功！exchangeName=" + binding.getExchangeName()+"，queueName=" + binding.getQueueName());
    }

    //添加消息
    public void addMessage(Message message){
        messageMap.put(message.getMessageId(),message);
        System.out.println("[MemoryDataCenter] 新消息添加成功！MessageId="+message.getMessageId());
    }

    //根据Id查询消息
    public Message getMessage(String messageId){
        return messageMap.get(messageId);
    }

    //根据Id删除消息
    public void removeMessage(String messageId){
        messageMap.remove(messageId);
        System.out.println("[MemoryDataCenter] 消息被移除！MessageId="+messageId);
    }

    //发送消息到指定队列
    public void sendMessage(MSGQueue queue,Message message){
        //先根据队列的名字找到该队列对应的消息链表
        LinkedList<Message> messages=queueMessageMap.computeIfAbsent(queue.getName(),k->new LinkedList<>());
        //再把数据添加到messages中
        synchronized (messages){
            messages.add(message);
        }
        //把消息也往消息中心插入一份
        addMessage(message);
        System.out.println("[MemoryDataCenter] 消息被投递到队列中！MessageId="+message.getMessageId());
    }

    //从队列中取消息
    public Message pollMessage(String queueName){
        //根据队列名查找对应的队列的消息链表
        LinkedList<Message> messages=queueMessageMap.get(queueName);
        if(messages==null){
            return null;
        }
        synchronized (messages){
            //如果没找到，说明队列中没有任何消息
           if(messages.size()==0){
                return null;
            }
            //链表中有元素，就进行头删
            Message currentMessage=messages.remove(0);
            System.out.println("[MemoryDataCenter] 消息从队列中取出！MessageId="+currentMessage.getMessageId());
            return currentMessage;
        }
    }

    //获取指定队列中消息的个数
    public int getMessageCount(String queueName){
        LinkedList<Message> messages=queueMessageMap.get(queueName);
        if(messages==null){
            return 0;
        }
        synchronized (messages){
            return messages.size();
        }
    }

    //添加未确认的消息
    public void addMessageWaitAck(String queueName,Message message){
        ConcurrentHashMap<String,Message> messageHashMap=queueMessageWaitAckMap.computeIfAbsent(queueName,k->new ConcurrentHashMap<>());
        messageHashMap.put(message.getMessageId(),message);
        System.out.println("[MemoryDataCenter] 消息进入待确认队列！messageId="+message.getMessageId());
    }

    //删除未确认的消息（消息已经确认了）
    public void removeMessageWaitAck(String queueName,String messageId){
        ConcurrentHashMap<String,Message> messageHashMap=queueMessageWaitAckMap.get(queueName);
        if(messageHashMap==null){
            return;
        }
        messageHashMap.remove(messageId);
        System.out.println("[MemoryDataCenter] 消息从待确认队列删除！messageId="+messageId);
    }

    //获取指定的未确认的消息
    public Message getMessageWaitAck(String queueName,String messageId){
        ConcurrentHashMap<String,Message> messageHashMap=queueMessageWaitAckMap.get(queueName);
        if(messageHashMap==null){
            return null;
        }
        return messageHashMap.get(messageId);
    }

    //从硬盘上读取数据，把硬盘中之前持久化存储的各个维度的数据都恢复到内存中
    public void recovery(DiskDataCenter diskDataCenter) throws MQException, IOException, ClassNotFoundException {
        //清空之前所有的数据
        exchangeMap.clear();
        queueMap.clear();
        bindingsMap.clear();
        messageMap.clear();
        queueMessageMap.clear();
        //1、恢复所有的交换机数据
        List<Exchange> exchanges=diskDataCenter.selectAllExchanges();
        for (Exchange exchange:exchanges){
            exchangeMap.put(exchange.getName(),exchange);
        }
        //2、恢复所有的队列数据
        List<MSGQueue> queues=diskDataCenter.selectAllQueues();
        for (MSGQueue queue:queues){
            queueMap.put(queue.getName(),queue);
        }
        //3、恢复所有的绑定数据
        List<Binding> bindings=diskDataCenter.selectAllBindings();
        for (Binding binding:bindings){
            ConcurrentHashMap<String,Binding> bindingMap=bindingsMap.computeIfAbsent(binding.getExchangeName(),k->new ConcurrentHashMap<>());
            bindingMap.put(binding.getQueueName(),binding);
        }
        //4、恢复所有的消息数据
        for (MSGQueue queue:queues){
            LinkedList<Message> messages=diskDataCenter.loadAllMessageFromQueue(queue.getName());
            queueMessageMap.put(queue.getName(),messages);
            for (Message message:messages){
                messageMap.put(message.getMessageId(),message);
            }
        }
    }
}
